1. Field of the Invention
The invention relates to apparatus for producing an upwardly directed drill hole in rock, deposits, or the like by drilling from a roadway, starting chamber or the like, having a basic unit to be disposed in the starting chamber, a drilling head or the like, a rotary drive for the drilling head, a train of rods--which may be assembled from a plurality of parts13 between the basic unit and a supporting body with a bearing housing for the drilling head, a slide which is axially displaceable relative to the supporting body and a clamping apparatus which is associated with the latter and which comprises clamping cylinders in which pistons connected to plates which may be applied to the wall of the drill hole may be displaced outwards by pressure medium and inwards by springs and/or pressure medium, and having feed cylinders interposed between the supporting body or the drilling head bearing housing on the one hand and the slide or parts disposed thereon on the other and containing pistons which may be acted upon at both ends by pressure medium, there being provided, in order to actuate the feed cylinders and the clamping apparatus, a pressure medium system which contains at least one common supply duct--which is to be fed by a pump on the basic unit and is guided through the train of drill rods or is formed thereby--for one set of sides of the clamping cylinders and one set of sides of the feed cylinders and contains a reversing valve, by means of which cylinder spaces of the feed cylinders may be optionally connected to the supply duct or may be released from pressure.
2. Description of the Prior Art
In a known apparatus of this type (German Patent No. 30 11 449), in order to actuate the feed cylinders and the clamping apparatus there is provided a common supply duct which divides into a branch leading to the feed cylinders and a branch leading to the clamping apparatus. Only downstream of the branching is a reversing valve provided in the guide path to the feed cylinders. The annular spaces of the feed cylinders or the full spaces thereof may be connected by means of the reversing valve to the supply duct, while the respective other spaces may be opened to an outlet. A counter pressure valve and parallel thereto a non-return valve with a reverse flow direction are provided in the branch of the entire supply line leading to the cylinders of the clamping apparatus.
The aforesaid reversing valve is actuated with pressure medium by a control pump, the drive of which is derived from the rotary drive movement of the drilling head. The control pump, the reversing valve and further accessory elements are disposed on the supporting body positioned in the drill hole during operation or on a part connected thereto.